Not sure how to start making patterns? Do you struggle with the maths of calculating accurate middle (gusset) pieces. This is the tool for you!

I have previously released a Inkscape extension that can automatically generate patterns from shapes drawn, such as bag side panels. Not everyone has access to or uses Inkscape, so I’m working on bringing that key functionality to an online tool. Nearly instant patterns for backpacks, bike bags (frame bags, top tube bags etc) and more.

Work in progress! Might have some bugs. Test with a paper model or scrap fabric before committing to your expensive materials.

Draw your shape by left mouse clicking or tapping on the canvas. Where you want a split/new pattern piece in the gusset (perimeter side loop) right click. Split points are shown with red markers. On mobile you can make them red split points after the shape is completed.

Add seam allowance by pressing enter or click the Finish Shape/Add Seam allowance button to complete the shape. A helpful 3D view also appears! You can adjust the seam allowance in the pattern generation options

Edit the shape after the seam allowance has been added by clicking and dragging points, or tapping and dragging.

Add red split points on desktop by right mouse clicking any point. On mobile, tap any point.

Delete points by right clicking once to turn to a red split point, then click again to delete. Mobile, tap to turn to red, then tap again to delete

Add new points by tapping/clicking anywhere along a line segment

Scaling is adjusted by either specifying the actual real world dimensions of each grid square, or chosing a line segment and specifying the known length of that segment

Background image for tracing is added by clicking the browse button, and opacity can be adjusted. If the background image has wonky perspective, please use my free perspective correction tool before tracing. No images are uploaded to me, this all runs locally on your device.

Pattern Generation: Specify how wide you want the bag to be (use the 3D view to visualise) and the seam allowance, then click Generate Pattern (or type P).

You will now have a automatically generated pattern, ready to cut out and sew!

Printing and Assembling:

Patterns must be printed at 100% or “Actual Size” or equivalent in your printer settings. Cut along the borders and tape the borders together.